Radar Environment RF

Generation

Dr. Steffen Heuel

Technology Manager Aerospace & Defense

Rohde & Schwarz Munich, Germany

Typical navigation radar scenario

2

Tx

TxTx

Tx

Rx

Rx1+Rx2

Rx

Return from land clutter

North

N

S

W E

South

EastWest

Turning navigation

radar antenna

Visualization on a radar screen

Echoes are displayed in so called “range cells“

Coherent radars can also measure speed and

can therefore also display an echo in a

“Doppler cell“

The larger the radar return signal, the larger

the radar cross section i.e. the object, the

larger the dot on the screen

Conventional Test set-up for navigation radar testing

Tx

TxTx

Tx

Rx

Rx1+Rx2

Rx

Return from land clutter

Test ship with

radar under test

on board

Artificial targets

deployed on sea

ı Test Concept for Navigation Radars

Mount a real radar under test on a boat

Deploy artificial targets at the sea

ı Test Concept for airborne radars

Set up a flight campaign with artificial targets or use civil aircrafts

ı Test concept for ground radars

Set-up field-test in large area to test performance

3

Motivation and Approach

4

Target SimulationSea Clutter Simulation

Field-to-lab

ReduceCost, complexity & test

time

ImproveAccuracy, reliability &

repeatability

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Sea clutter generation

Radar Detection

Probability Density Function

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𝑃𝐹𝐴 False Alarm Probability

𝑃𝑀 Probability of Missing a Target

𝑃𝐷 Probability of Missing Detection

Rayleigh Distribution

Rice DistributionThreshold

Typical Sea Clutter

PPI view

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Range

Re

ce

ive

dP

ow

er

How to simulate

time and spatial

correlated sea

clutter?

ı Capillary waves

Wavelength of centimeters or less

Driven by local wind gusts

Stochastic model

ı Gravity waves

Wavelength of a few hundred meters down

to a meter

Created by stable winds over a large area

Physical model

Two scale model of the sea surface

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Courtesy of waterswaytravel.com

Courtesy of wikipedia.org

Two scale model of the sea surface

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Capillary waves

Stochastic model

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ı Following Rayleigh

distribution

ı SIRP procedure can be

used for generation if IQ data

is available

ı Otherwise uncorrelated

Rayleigh distributed noise

with mean level according to

physical model

Rayleigh

distributed

capillary waves

Rayleigh distributed noise:

Δy

Δx

ı Use established model to simulate

sea surface

Parameters: average wave height and

period, spreading factor, sampling

frequency

ı Transform height of sea surface to

have a Chi-distribution

Transformation is performed with the

help of memoryless nonlinear

transformation (MLNT)

Shape parameter can be estimated

using available formulas

Gravity Waves

Physical Model

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Simulation of sea surface heights

arbitrary

distributed

gravity waves

Δy

Δx

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Data verification and signal

generation

IPIX datarecorded on Canadian East Coast in 1993

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KS-Test passed in 83% using

significance level α=0.05

Environment to multisegment waveform

|A|

R

|A|

R

|A|

R

...

Radar PPI

Map environment

to waveforms

ı Multisegment waveform (MSW) consists of multiple independent waveforms

ı Each radar “TX Pulse” triggers a segment (and the next segment…)

….

….

Segment

Marker

Segment

Marker

Segment

Marker

timeI/Q data

Environment simulation using multisegment

waveform (MSW)

Radar echo generation and environment simulation

R&S®SMW

Radar under

Test

RX

Antenna

Headmarker

TX Puls

Marker

+RF Out

TX

DigIQ,

LAN,

Ref

R&S®FSW

RF In

R&S®Radar Echo Generation

Sea Clutter

Additional RF

Signals, Echoes,

Jamming etc.

Measurement setup in the laboratory

Radar PPI

X-Band Radar TRX

Vector Signal

Generator

Dummy Load

Circulator

Signal and

Spectrum Analyser

Simulated Sea Clutter

Sea clutter

Moving target

Simulation

X-Band Radar

PPI Screenshot

Max range

set to 1.5NM

Radar suppresses sea

clutter in close range

Recorded Sea Clutter

ı Single radar echo

signal, moving target

with 100m/s in 5NM

range

ı Recorded sea clutter

Sea clutter

Moving target

Max range

set to 12NM

Test of Interference Rejection

ı Coastline

ı Sea clutter in close

range

ı R&S®Pulse

Sequencer Software

to add interference /

jamming signals

ı Verify interference

rejection

Interference rejection

Switched off

Artefacts due to another

present solid state radar

Thank you for

your attention!